Proving Simple Physics can Grant Quantum Computation

It is probably not surprising that quantum computers, which may one day solve the most complicated problems man knows of, are themselves based on complicated physics. According to researchers at MIT, IBM, Masaryk University, the Slovak Academy of Sciences, and Northeastern University though, quantum computers based on spin may not need to be all that complicated. They show this by proving that one does not require high dimensions of entanglement to scale performance with particle count.

Within spin-based quantum computers are particles of one kind or another whose spin states are entangled with each other. This means that when you measure the spin of one particle in a chain, you know about the spins of all of the particles. Previous work showed that as long as the particles can have over 14 spin-states entangled, adding particles to the chain will increase computing power. With so many separate states being linked though, adding particles is extremely complicated, but the researchers have found that performance can scale when the dimensionality is as low as three. This was achieved by showing it is possible to change any one chain of spin-states to another without changing the net energy of the chain.

This discovery could greatly influence the future of quantum computers by making them simpler to construct, but there is a catch. The current research shows relationship between chain-length and computing power is logarithmic, so there are diminishing returns compared to the linear relationship of chains with more entangled spin-states.